Bacillus subtilis RSKK246 was found to produce approximately a 65-kDa alpha -amylase enzyme. A gene was isolated encoding ol-amylase activity that corresponded to this size and was inserted into pUC18 plasmid which was transferred to Escherichia coli. An approximately 1.7kbp fragment, which contains a whole alpha -amylase gene, was excised and inserted into pUB110 and then transferred into the different B. subtilis strains including RSKK246, RSKK243, RSKK244, YB886 and DREAM. The alpha -amylase gene was cloned into the plasmids and expressed with its own promoter, and this promoter sequence seemed to function in the E. coli and in all B. subtilis strains. Specific activity of the cloned enzyme was found to be higher than the native enzyme and molecular weight of the gene product remained the same in all other strains suggesting that it is resistant to the proteolytic attacks of these organisms.